There are several methods to support multiple floors or a roof structure of a building, that is, by using a load bearing wall or by using a beam which is supported by posts on both sides of the beam. Should a wall require any windows a beam is installed above the window and columns are installed on both sides of the window. A high-rise or larger type buildings, uses columns and beams to support the additional floors and roof loads above. On the other hand, smaller buildings also use walls to support the weight of additional floors or roof load above. These load bearing walls can be made of solid masonry, concrete or even as a framed wall using wood or metal framing members typically spaced 16-24 inches apart. A non-load bearing wall can also be made using wood or metal framing members, the wall only supports itself not a roof or floor load above. The non-load bearing wall can also be built the same way, however the structural capacity of the framing members are less and therefore the material costs are less expensive.
The construction of a wall varies based on the type of materials that are used. For example a solid concrete or masonry wall does not need to be laterally supported, because the wall is connected horizontally from say one masonry block to another masonry block. On the other hand, a post and beam type construction needs to be horizontally braced somewhere within that building otherwise the building would collapse if the wind or an earthquake would cause the building to move horizontally. Usually that is done by adding diagonal braces that criss-cross between the columns or by adding a solid wall somewhere within the building structure. When a smaller wood or metal framed wall has a similar problem, that is, the framing members need to be supported between each other using by applying plywood over the framing members. The plywood acts a shear wall, by not allowing the framing members to fall down like “domino's”.
Typically the higher the wall, the thicker the wall becomes. This occurs because if a tall wall is not laterally supported (braced by another structure) then the wall will bend. For example, a masonry wall can have a pilaster added, that is, a column attached to the wall and made of the same material.
Another way to stop a wall from bending is adding a lateral support; that could be in the form of adding a horizontal stud in the middle of a wood wall or a horizontal channel in the middle of a steel wall also known as a purlin. With wood or metal framing members require fire stops (a horizontal framing member between vertical framing members) at walls over eight feet and between one floor and another floor at the floor line. When a wall is required to be taller than what is required by building codes, the wall width or the wood studs or metal channels are required to be wider to accommodate the increase wall height. In addition the higher the wall, the more need there is to have intermediate horizontal bracing members. For wood construction, these usually are accomplished by adding horizontal wood studs between the vertical studs. For metal construction this is accomplished by adding a lateral channels that pass through the holes between each of the C channels. In tubular metal construction, two opposite sides of the tube are removed and the remaining two sides are attached to the vertical tubular metal supports. In heavy steel construction, known as red iron, horizontal purlins are installed between the vertical steel supports. In all the various constructions, the horizontal lateral supports reduce the amount of bending caused by horizontal wind loads as well as the vertical load of which there are designed to support like roof or floor loads from above.
When constructing a single or multiple floors between the ground level and the roof, a fire stop is required between floors. This is accomplished by installing a solid horizontal plate break in the wall construction separating the wall construction between one occupied floor and another floor. Typically, this fire stop occurs when the end of the floor joist rests upon the wall. In wood construction it is usually using two wood plates. One plate is attached to each stud and another plate is installed over the lower plate to overlap the individual wall sections together. The floor joists are then installed over the top plate and a ledger board is installed perpendicular to the floor joists thereby connecting each joist. Wood decking is installed over the floor joists and then individual wall sections are installed over the floor decking. Metal light gauge framing is also built in the same way, however only one base plate is used at the top and bottom of the metal channels. The metal floor joists are both secured to the top wall base plate as well as the ledger channel at the end of the floor joists. For post and beam construction, for either heavy structural steel or concrete, a beam is used to support the floor load between columns and a fire stop is required when the exterior finish material does not stop between floors.
Typically wood or metal framed wall construction must be secured to a foundation or concrete slab either by anchor bolts embedded within a concrete wall and or attaching tie down supports which are secured to the metal or wood studs and then anchored into the foundation or foundation.
Concrete construction has changed over the years since the days of the Roman Empire where concrete was initially used. From the early concrete building structures, concrete wall construction has developed into today's construction uses ICF's (insulated concrete forms) to build concrete walls. Now as energy has become more expensive, these ICF's have reduced the amount of concrete within the wall by adding more insulation thereby creating columns and beams within the ICF's. These ICF's have a very rigid system with no flexibility on where to install the beams or columns.
Structural insulated panels or SIP's have a foam core with exterior skins usually plywood glued to the foam. Sometimes metal or wood is installed within the foam core and the wood or metal is connected between the panels for additional support. SIP's have a very limited load bearing capacity due to the structural limitation in the design of the panels. The use of SIP's have been limited to one or two story building and have never been used in conjunction with precast or poured-in-place concrete walls.
Rigid insulation boards have been installed on metal channels for years and more recently rigid insulation has been glued onto metal channels as a thermal barrier. Insulating blocks have embedded channels within insulation blocks also embedding the metal channels within the rigid insulation. Some insulated concrete forms (ICF's) have embedded plastic connectors within their rigid insulation blocks also separating the rigid foam from the plastic connectors. Structural insulated panels (SIP's) have no thermal break when wood or metal is added at the connections of adjacent panels. None of the systems has a interior and sheathing insulation combined as well as creating a thermal break within a wall forming structure.
Thin faced precast concrete wall panels have been using light gauge metal framing for the structural backing for a few years now. When the concrete is poured face up, insulation supports the concrete until it has cured, while pouring the concrete face down in a forming bed, the light gauge metal framing is suspended over the forming bed and the metal channel is typically embedded into the concrete facing and usually no thermal break is accomplished. These systems do not combine the wall and sheathing insulation, plus have that thermal break as well as the flexibility to install columns and beams within the structure.
Thin cementitious material has been applied over foam, however usually to make a block, and the entire block is entirely encased with the cementitious material. Sometimes a wall panel has also been fully encased with the cementitious material and recently an ICF block has been partially encased with the cementitious material. Cementitious materials have not applied to wall panels where the cementitious materials have had the thermal break between the interior and exterior surfaces.
Modular buildings have been very limited in their design and functionality of their superstructure. Modular construction has been typically limited to wood framed building and some have been developed using steel as a column and beam substructure. Concrete has had limited exposure in modular buildings, as well as the use of a insulated core to form concrete beams and columns within the exterior walls and common walls between modular buildings.
Today, more and more steel or concrete post and beam buildings are being built. Construction techniques for building walls have been changing significantly including metal channel framing and stay-in-place insulated forms where concrete is installed within these forms.